Some recently available vehicles are capable of monitoring the area around a vehicle by using an on-vehicle camera. There is known a technology that captures the image of a forward view from the vehicle by using an on-vehicle camera mounted on the front of the vehicle, determines the position of a lane by analyzing the captured image, and detects obstacles and pedestrians. Further, there is a widespread technology that uses an on-vehicle camera mounted on the rear of a vehicle to display the image of a rearward view from the vehicle on a monitor screen during backward movement of the vehicle to provide driving assistance to a driver of the vehicle. Furthermore, there is a proposed technology that uses on-vehicle cameras mounted on the front, rear, left, and right of a vehicle to synthesize images captured by the on-vehicle cameras to display an overhead view of the area around the vehicle (Patent Literature 1).
All the above technologies are developed on the assumption that the on-vehicle cameras capture the image of a predetermined monitoring region. The on-vehicle cameras therefore need to be mounted in an appropriate position and at an appropriate angle. An on-vehicle camera used to monitor the forward or rearward view from the vehicle needs to be mounted at a predetermined angle in both the left-right and front-rear directions with respect to the traveling direction of the vehicle. Further, when an all-around view from the vehicle is to be displayed by using images captured by on-vehicle cameras mounted on the front, rear, left, and right of the vehicle, the on-vehicle cameras need to be mounted at respectively predetermined angles.